This invention relates generally to program controlled manipulators and particularly to adapting programmed manipulator activity to unprogrammed variations of work process related parameters.
As distinguished from conventional machine tools wherein the primary axes of motion are axes of translation corresponding to the coordinate axes of a rectangular triordinate system, manipulators achieve greater flexibility by including axes of rotation to effect orientation of a tool or workpiece carried thereby. By virtue of this greater flexibility, particularly true of articulated or anthropomorphic machines, programmable manipulators are applied to tasks requiring controlled motion and which previously were performed manually even though the work environment posed serious health hazards. Examples of such work include seam welding, spray coating, and rough casting cleaning. The principal obstacle in any such application is the in-process adaptation of motion control to unprogrammed variations of process parameters such as weld pool variations with seam gaps, coating fluent viscosity variations with temperature and humidity, and the cutting torque variations with rough casting flash and gate. While there are a number of procedures for altering a program path to accomodate sensed conditions requiring deviations, it has heretofore been unknown to automatically vary the velocity of the motion of the program controlled manipulator to accommodate process parameters such as those mentioned. Nevertheless, these tasks as well as many others, are readily made adaptable to nonprogrammed parameter variations by permitting the programmed motion to be subject to velocity variations defined in accordance with a suitable function relating a measured process parameter and the path velocity.
It is, therefore, an object of the present invention to provide a manipulator and control for moving a function element in response to programmed input signals describing the motion and responsive to unprogrammed variations of a process parameter to vary the velocity of motion.
It is a further object of the present invention to provide a manipulator and control for moving a function element in accordance with a preprogrammed description of the motion and selectively responsive to unprogrammed variations of a work process parameter to vary the velocity of motion.
It is a still further object of the present invention to provide a manipulator and control for moving a function element in accordance with a preprogrammed description of the motion and responsive to a function relating values of a measured process parameter to velocity to vary the velocity of motion.
It is a still further object of the present invention to provide a manipulator and control for moving a function element in response to input signals defining positions relative to a rectangular coordinate system and path velocities therebetween and responsive to the measured values of the work process parameter for varying the effective path velocity during an automatic mode of operation.
Further objects and advantages of the present invention shall become apparent from the accompanying drawings and the description thereof.